If you are talking about "de-interlacing", you have FieldsKit and Nattress for FC.
There is also an standalone free application called "Jes deinterlacer".
Compressor has also very good deinterlacing options.
rafael

Most of the 'smart' deinterlacers do this by using motion detection to retain information that would be common between fields - in this way, they try to keep the vertical resolution up whilst having a progressive look.

The problem is that they can cause atifacting when they get confused, which is often more distracting that a straight de-interlace. Whatever you do to interlaced material, it will not be progressive when you finish (unless the camera shot PsF) - you can't fake it entirely.

When you talk about 'interpolation' you usually mean the opposite of this process - you are creating extra fields or frames from material, such as when you use optical flow, or 4-field interpolation for smoother slo mo. With a de-interlace, you are trying to take away fields, and this is trickier, as the image moves between them - it's impossible to just double these up to make a single frame without guessing at the motion.

Apart from graphics and small text, de-interlacing holds up much better in HD than it used to in SD material. For this reason, since moving to HD entirely, I bother a lot less now with 'smart' deinterlacers.

I've only just learnt FCP and Motion. Haven't got to After Effects (that will be a fair while down the track - I've heard it's hard to learn), and not sure if I have compressor (don't think it came in the package).